1. Field of the Invention
The present invention relates to warning lights and particularly to collision avoidance lights having no moving parts which are suitable for use on aircraft and other vehicles. More specifically, this invention is directed to a compact and efficient device for producing highly visible flashes of light and especially to a light assembly wherein light generated by a flash tube or incandescent lamp is directed, in part by reflection and in part by refraction, so as to provide the optimum radiation pattern for the intended use. Accordingly, the general objects of the present invention are to provide novel and improved apparatus of such character.
2. Description of the Prior Art
While not limited thereto in its utility, the present invention is particularly well suited for use as a replacement for the rotating beacon type of light which has found widespread usage as an anti-collision warning on aircraft. Such rotating beacons typically comprise a constantly energized lamp and a rotating or oscillating mirror, the lamp and mirror being covered by a transparent dome which may also function as a lens. Movement of the mirror causes the light generated by the lamp to appear to an observer to be flashing. Since a rotating beacon requires a motor and other moving parts, such lights inherently have a service life which is short when compared to lights with no moving parts. Accordingly, relatively frequent periodic maintenance or replacement is required of rotating beacon type anti-collision lights.
A collision avoidance light for aircraft usage, and the same requirement is imposed by many emergency land and water vehicle applications, must provide a highly visible warning signal. The requirement for high visibility dictates that the light which is produced be characterized by high intensity and appear to an observer as flashes or pulses. The generation of such high intensity light pulses, however, must be accomplished without imposing unduly large power consumption requirements on the vehicle's electrical system. Power consumption requirements aside, there is a limit to the amount of light which can be generated by a given source such as, for example, a halogen lamp or a gaseous discharge tube. Obviously, the brighter the light which is generated, the better the anti-collision function will be performed. The requirement of high intensity light pulses coupled with the need for reasonable power consumption dictates that the energy in the visible spectrum which is generated by a given source be used as efficiently as possible. Accordingly, the generated light must be collected and directed so as to maximize visibility taking the particular use environment into account. In the case of an aircraft collision avoidance warning, the requisite radiation pattern is defined by FAA Specification FAR PART-23,1401 and PART 25,1401 and 91.33(c).
There has been a long standing desire for a compact and efficient light, capable of employing either a gaseous discharge tube or a halogen lamp as the light source, which meets the above-referenced FAA Specification and is capable of installation on aircraft either as original equipment or as a replacement for an existing rotating beacon type anti-collision light. While collision avoidance lights having no moving parts have previously been available, these prior lights could not be installed in place of an existing rotating beacon without difficult and expensive rewiring and, in any event, the prior lights were relatively inefficient in their use of the generated light energy and/or in the consumption of electrical power.